Orbicules in angiosperms: Morphology, function, distribution, and relation with tapetum types

Huysmans, Suzy; El‐Ghazaly, Gamal; Smets, Erik

doi:10.1007/bf02856566

Cited by 156 publications

(103 citation statements)

References 144 publications

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“…2P), in which the bulged structure in osabcg26 exine surface was obscure at stage 13, indicating possible overdeposition of lipidic precursors onto the pollen exine surface. Consistent with the role of characteristic orbicules/Ubisch bodies in exporting tapetumsynthesized sporopollenin precursors across the hydrophilic cell wall to the anther locule (Huysmans et al,1998;Li et al, 2010Li et al, , 2011, we observed the regular shape of orbicules containing electron-dense lipidic precursors along the tangential inner surface of wildtype tapetal cells (Fig. 3, I and O); in contrast, the morphological structure of osabcg26 orbicules/Ubisch bodies was abnormal, which contained more electrondense lipidic substances (Fig.…”

Section: Characterization Of Osabcg26supporting

confidence: 83%

Two ATP Binding Cassette G (ABCG) Transporters, OsABCG26 and OsABCG15, Collaboratively Regulate Rice Male Reproduction

et al. 2015

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Male reproduction in higher plants requires the support of various metabolites, including lipid molecules produced in the innermost anther wall layer (the tapetum), but how the molecules are allocated among different anther tissues remains largely unknown. Previously, rice (Oryza sativa) ATP binding cassette G15 (ABCG15) and its Arabidopsis (Arabidopsis thaliana) ortholog were shown to be required for pollen exine formation. Here, we report the significant role of OsABCG26 in regulating the development of anther cuticle and pollen exine together with OsABCG15 in rice. Cytological and chemical analyses indicate that osabcg26 shows reduced transport of lipidic molecules from tapetal cells for anther cuticle development. Supportively, the localization of OsABCG26 is on the plasma membrane of the anther wall layers. By contrast, OsABCG15 is polarly localized in tapetal plasma membrane facing anther locules. osabcg26 osabcg15 double mutant displays an almost complete absence of anther cuticle and pollen exine, similar to that of osabcg15 single mutant. Taken together, we propose that OsABCG26 and OsABCG15 collaboratively regulate rice male reproduction: OsABCG26 is mainly responsible for the transport of lipidic molecules from tapetal cells to anther wall layers, whereas OsABCG15 mainly is responsible for the export of lipidic molecules from the tapetal cells to anther locules for pollen exine development.

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Section: Characterization Of Osabcg26supporting

confidence: 83%

Two ATP Binding Cassette G (ABCG) Transporters, OsABCG26 and OsABCG15, Collaboratively Regulate Rice Male Reproduction

et al. 2015

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“…Orbicules (i.e. Ubisch bodies) are sporopollenin particles seen in secretory tapeta, which are thought to be involved in transporting materials from the tapetum to microspores (Huysmans et al, 1998). Orbicule development was seen in the mutant but was decreased in size compared with the wild type, and by late stage 10 it showed a reduction of both the electron-opaque central region and the surrounding electron-dense sporopollenin (Fig.…”

Section: Defects Of Anther Wall and Pollen Development In Ptc1mentioning

confidence: 99%

“…This may reflect the differences in tapetal development in monocots and dicots. Rice and Arabidopsis both have secretory tapeta where the cells remain intact until their disintegration (Huysmans et al, 1998;Furness and Rudall, 2001). However, the tapeta of rice and other cereals exhibit characteristic orbicules/Ubisch bodies, which are thought to export tapetum-produced sporopollenin precursors across the hydrophilic cell wall to the locule.…”

Section: Ptc1 Determines a Conserved And Diversified Switch Of Apoptomentioning

confidence: 99%

PERSISTENT TAPETAL CELL1Encodes a PHD-Finger Protein That Is Required for Tapetal Cell Death and Pollen Development in Rice

et al. 2011

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In higher plants, timely degradation of tapetal cells, the innermost sporophytic cells of the anther wall layer, is a prerequisite for the development of viable pollen grains. However, relatively little is known about the mechanism underlying programmed tapetal cell development and degradation. Here, we report a key regulator in monocot rice (Oryza sativa), PERSISTANT TAPETAL CELL1 (PTC1), which controls programmed tapetal development and functional pollen formation. The evolutionary significance of PTC1 was revealed by partial genetic complementation of the homologous mutation MALE STERILITY1 (MS1) in the dicot Arabidopsis (Arabidopsis thaliana). PTC1 encodes a PHD-finger (for plant homeodomain) protein, which is expressed specifically in tapetal cells and microspores during anther development in stages 8 and 9, when the wild-type tapetal cells initiate a typical apoptosis-like cell death. Even though ptc1 mutants show phenotypic similarity to ms1 in a lack of tapetal DNA fragmentation, delayed tapetal degeneration, as well as abnormal pollen wall formation and aborted microspore development, the ptc1 mutant displays a previously unreported phenotype of uncontrolled tapetal proliferation and subsequent commencement of necrosis-like tapetal death. Microarray analysis indicated that 2,417 tapetum-and microspore-expressed genes, which are principally associated with tapetal development, degeneration, and pollen wall formation, had changed expression in ptc1 anthers. Moreover, the regulatory role of PTC1 in anther development was revealed by comparison with MS1 and other rice anther developmental regulators. These findings suggest a diversified and conserved switch of PTC1/MS1 in regulating programmed male reproductive development in both dicots and monocots, which provides new insights in plant anther development.

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“…The presence/absence of orbicules and their morphology can provide additional palynological characters that might have a phylogenetic significance (e.g., Raj and El-Ghazaly 1987;Huysmans et al 1998;Vinckier and Smets 2002). Orbicules are small sporopollenin particles that can be produced in species with a secretory tapetum (Huysmans et al 1998(Huysmans et al , 2000.…”

Section: Introductionmentioning

confidence: 99%

“…Orbicules are small sporopollenin particles that can be produced in species with a secretory tapetum (Huysmans et al 1998(Huysmans et al , 2000. Until now, the presence of orbicules has not been investigated systematically in Lamiaceae (Huysmans et al 1998(Huysmans et al , 2000.…”

Section: Introductionmentioning

confidence: 99%

A Search for Phylogenetically Informative Pollen Characters in the Subtribe Salviinae (Mentheae: Lamiaceae)

Moon¹,

Vinckier

Walker

et al. 2008

International Journal of Plant Sciences

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The pollen morphology and ultrastructure of the subtribe Salviinae were investigated with light, scanning electron, and transmission electron microscopy. In addition, cladistic analyses of the obtained morphological data, supplemented with rbcL data from GenBank, were conducted in order to assess the phylogenetic signal of palynological characters. Salviinae pollen is small to large, oblate to prolate in shape, with a circular to slightly elliptic amb, and mostly hexacolpate. Perovskia abrotanoides appears to be distylous and shows a significant pollen dimorphism between pin and thrum flowers. The sexine ornamentation of the genera Lepechinia and Chaunostoma is perforate, while the ornamentation of other genera is bireticulate. Perovskia expresses a unique type of sexine ornamentation. The sexine ornamentation variation in Salvia has systematic importance but only partly corresponds with current phylogenetic hypotheses. Unbranched columellae and a continuous, granular endexine are hypothesized to be a symplesiomorphic condition in the tribe Mentheae. Our combined phylogenetic analyses show that the addition of palynological characters contributes to improved resolution and also increases bootstrap support values in comparison with molecular phylogenetic analyses.

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Orbicules in angiosperms: Morphology, function, distribution, and relation with tapetum types

Cited by 156 publications

References 144 publications

Two ATP Binding Cassette G (ABCG) Transporters, OsABCG26 and OsABCG15, Collaboratively Regulate Rice Male Reproduction

Two ATP Binding Cassette G (ABCG) Transporters, OsABCG26 and OsABCG15, Collaboratively Regulate Rice Male Reproduction

PERSISTENT TAPETAL CELL1Encodes a PHD-Finger Protein That Is Required for Tapetal Cell Death and Pollen Development in Rice

A Search for Phylogenetically Informative Pollen Characters in the Subtribe Salviinae (Mentheae: Lamiaceae)

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